An extension of the JUnit org.junit.runners.BlockJUnit4ClassRunner – the default
runner for JUnit 4 test classes – which executes the test methods of
the test class concurrently, if you annotate it like this:

@RunWith(ParallelRunner.class)
public class FooTest {
...
}

You can specify the maximum number of parallel test
threads using the system property maxParallelTestThreads.
If this system property is not specified, the maximum
number of test threads will be the number of
available processors.